[Tim W]

To get struck a sheep has to have a nice environment for a fly to lay her eggs    = moist and warm fleece
Colour may only be relevant in that a black fleece may be warmer than a white fleece?

Biggest factor in determining a sheep's predisposition to flystrike is length of tail (Uni. Of Bristol data)
Long tail = dags= strike
Short tail = clean bum = less strike
2nd biggest factor is local environment---weather/dirt/damp and local fly population

I have the report somewhere but I think it's a paper version  so may be hard to find in my 'filing system'

[wayfarer]

Last two years I have had 2 southdowns and 2 zwartble crosses and both years it was a southdown that got strike.  This year I only have zwartble corsses so  .  I thought that it was probably more to do with the southdowns having a fleeece that seemed to soak up moisture whereas the zwartbles don't seem to stay wet for as long.

[Azzdodd]

Funny you say that time the zwarbles have shorter tails all my white sheep have long tails bar ram lambs I dock as the slaughter house prefer them like. I stood watching them all today (all sheered now) and the big long white tails don't have move some!   

[JulieWall]

There's a certain kind of afternoon and evening which the blow flies love, it's hard to describe exactly. Usually it has been a fine day followed by a very still, sticky warm evening. No rain but there's a heaviness in the air similar to that preceding a thunderstorm, I can feel it better than describe it I'm afraid.
It's hard to keep some breeds of sheep clean on wet spring grass, they just get watery squits if it's too rich for them. Then you get squitty individuals within any breed, mostly the poor doers. It's worth considering how clean a ewe generally keeps when selecting for replacements, as well as all the other considerations.

[smee2012]

Biggest factor in determining a sheep's predisposition to flystrike is length of tail (Uni. Of Bristol data)
Long tail = dags= strike
Short tail = clean bum = less strike

That's interesting you should say that, as Zwartbles sheep don't have docked tails - it's part of the breed standard. Having said that though, they don't have those thick woolly tails, they are more like the ovine version of a whippet or Vizla tail!

We live at a fairly low altitude here in Shropshire - 100 m above sea level - but we are on top of a bit of a hill and so it's windy most of the time here. I wonder if that makes a difference to fly populations.

[Hellybee]

Over zealous docking too!     Sme of ours have really short tails, more like stumps, thy have no control over they're tails, just as bad as a long tail in our experience...

[Tim W]

I questioned the length of tail thing too----but extensive data shows that long tails = strike
I have no doubt that most of these tails were dirty and hence more prone to strike
My shedders have long tails (no wool and hence clean tails) and I think it helps keep the flies away